// Copyright 2025 International Digital Economy Academy
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

///|
fn build_literals_only_payload(
  src : Bytes,
  start : Int,
  block_len : Int,
  level : Int,
) -> Bytes raise ZstdError {
  if level < 10 || block_len < 32 {
    return b""
  }
  if start < 0 || block_len <= 0 || start + block_len > src.length() {
    return b""
  }
  let literals : Array[Byte] = Array::new()
  append_bytes(literals, src, start, block_len)

  let payload : Array[Byte] = Array::new()
  append_best_literals_section(payload, Bytes::from_array(literals))
  append_sequence_count(payload, 0)
  let encoded = Bytes::from_array(payload)
  if encoded.length() >= block_len {
    return b""
  }
  encoded
}